CFD in AIAA’s Year in Review 2012

Are we too far into 2013 to take a look back at 2012?

As always, the December issue of AIAA’s Aerospace America magazine presents an annual Year in Review. The articles in this issue are written by representatives of each of AIAA’s technical committees. Besides providing a great summary of the current state of affairs in a wide range of technical disciplines, it shows how and where CFD is having an impact.

The Year in Review issue is my favorite issue of the only year and the only issue of the magazine I keep. I have them all since 1980, the year I joined AIAA as a student.

aero-amer-yir-stack

Multidisciplinary Design Optimization

  • Researchers at the Univ. of Michigan coupled CFD with FEA to optimize aeroelastic tailoring involving hundreds of variables.
  • NASA Glenn has developed an open-source framework for MDO called OpenMDAO.

Structural Dynamics

  • Wind tunnel testing by Gulfstream acquired data on flutter to be used to calibrate lower-than-CFD fidelity aero codes.

Survivability

  • Although not CFD, the report about the accumulation of ice in and around the combustion chamber of an operating aircraft engine was fascinating.

Aeroacoustics

bancii-header

Sample cases of aircraft noise from the BANC-II workshop website.

  • Results from the 2nd Workshop on Benchmark Problems for Aircraft Noise Computations (BANC-II) indicated good matches between computation and experiment but not as good results for radiated noise.

Aerodynamic Measurement Technology

  • Velocity distribution on the surface of a flared cone model were measured by JAXA during a wind tunnel test that employed a long-range micro-PIV system. Sufficient agreement with CFD was obtained to help explain transition on that model.

Applied Aerodynamics

Drag Prediction Workshop results for drag coefficient versus grid refinement. Image from DPW5 website.

Drag Prediction Workshop results for drag coefficient versus grid refinement. Image from DPW5 website.

  • Results from the first AIAA Aeroelastic Prediction Workshop indicate where key improvements need to be made in CFD modeling to improve its comparison with data. Those improvements are oscillating shock waves, shock-induced flow separation, and wind tunnel wall influence.
  • CFD was applied to NASA’s N+2 program on supersonic transport and helped achieve low-boom cruise without performance degradation.
  • The DoD’s CREATE program released three CFD programs during 2012:
    • KESTREL v3.0 (fixed wing CFD)
    • HELIOS v3.0 (rotary wing CFD)
    • CAPSTONE v3.0 (grid generation)
  • The 5th Drag Prediction Workshop was held and used the NASA Common Research Model geometry for a turbulence model study.
  • NAVAIR used KESTREL to compute sound levels for a UCAV.

Atmospheric and Space Environments

  • While not CFD, this is fascinating to anyone who’s a weather junky. Pop-up storms can be predicted via “now-casts” from a website at the Univ. of Alabama at Huntsville. An algorithm uses satellite data to predict which clouds are likely to produce rain. The system is called SATCAST.

Fluid Dynamics

Power spectral density on a nose gear as computed by Exa. Image from a paper by Exa and Gulfstream.

Power spectral density on a nose gear as computed by Exa. Image from a paper by Exa and Gulfstream.

  • Gulfstream and EXA showed promising results for computation of landing gear noise.
  • NASA Langley’s FUN3D code demonstrated capability for design optimization of unsteady flows.
  • CFD is being used to compute the thermal environment of the Mars Science Lab’s heat shield using data obtained during its actual decent to the Martian surface.

Ground Testing

  • Sonic boom tests at NASA’s Unitary Plan Wind Tunnel collected data that will be used to validate CFD codes.
  • A test of the parachute system for the crew exploration vehicle will also provide data for CFD validation.

Modeling and Simulation

  • To support the ability of flight simulators to model post-stall behavior, computational analysis [presumably CFD] was used to create one such model.

Meshing, Visualization, and Computational Environments

Advanced feature detection in FieldView. Image copyright (c) Intelligent Light 2012.

Advanced feature detection in FieldView. Image copyright (c) Intelligent Light 2012.

  • Intelligent Light introduced a new method for detecting flow features in large-scale unsteady CFD simulations.
  • Visualization of DNS results provided insight into very long streamwise vortices.
  • University of Alabama at Birmingham, JAXA, and Penn State have each developed independently novel mesh generation and overset grid assembly tools.
  • Pointwise is developing techniques to streamline the overset grid assembly process.
  • The first Mesh Quality Workshop was held to establish a baseline for the effect of mesh quality on solution accuracy and convergence.

Aerodynamic Decelerator Systems

  • DoD’s collaborative research programs have coupled CFD with wind tunnel and air-drop tests to provide unique insights into the performance of decelerators.

Balloon Systems

  • A JPL led team validated CFD models of hot air balloons designed for future missions to Saturn’s moon Titan.

General Aviation

The Transition from Terrafugia shown here as a driving aircraft as opposed to a flying car.

The Transition from Terrafugia is shown here as a driving aircraft as opposed to a flying car.

  • Not CFD but a sign, as they say, that the future is already here but just not equally distributed. Terrafugia completed testing of its flying car and may begin production during 2013. [Flying cars!]

Computer Systems

  • Disappointingly, there are no direct references to CFD. Much of the review is devoted to spacecraft and CubeSats.
  • IBM’s Blue Gene/Q at Livermore is cited as the world’s fastest at 16.32 petaflops.
  • “The purpose of computing is insight.” Insight enables design. Design is refined through simulation.

Air-Breathing Propulsion Systems Integration

Channeled centerbody inlet mounted beneath an F-15. Image from Aviation Week.

Channeled centerbody inlet mounted beneath an F-15. Image from Aviation Week.

  • Flight tests of a channeled centerbody inlet experiment produced data for use in CFD validation.
  • Cart3D was used for the shape optimization of a single-aisle transport wing and ultra-high-bypass fan nacelle.

Propellants and Combustion

  • A team led by Pratt & Whitney Rocketdyne tested rotating detonation waves to improve CFD modeling of the same.

I won’t pretend that my summary is comprehensive so please feel free to let me know if I missed something.  But it’s great to be involved in a field like CFD that’s having such a broad impact across the aerospace community.

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